Mechanical properties of thromboemboli play an important role in the efficacy of endovascular thrombectomy (EVT) for acute ischemic stroke. However, very limited data on mechanical properties of ...human stroke thrombi are available. We aimed to mechanically characterize thrombi retrieved with EVT, and to assess the relationship between thrombus composition and thrombus stiffness.
Forty-one thrombi from 19 patients with acute stroke who underwent EVT between July and October 2019 were mechanically analyzed, directly after EVT. We performed unconfined compression experiments and determined tangent modulus at 75% strain (Et75) as a measure for thrombus stiffness. Thrombi were histologically analyzed for fibrin/platelets, erythrocytes, leukocytes, and platelets, and we assessed the relationship between histological components and Et75 with univariable and multivariable linear mixed regression.
Median Et75 was 560 (interquartile range, 393–1161) kPa. In the multivariable analysis, fibrin/platelets were associated with increased Et75 (aβ, 9 95% CI, 5 to 13) kPa, erythrocytes were associated with decreased Et75% (aβ, −9 95% CI, −5 to −13) kPa. We found no association between leukocytes and Et75. High platelet values were strongly associated with increased Et75 (aβ, 56 95% CI, 38–73).
Fibrin/platelet content of thrombi retrieved with EVT for acute ischemic stroke is strongly associated with increased thrombus stiffness. For thrombi with high platelet values, there was a very strong relationship with thrombus stiffness. Our data provide a basis for future research on the development of next-generation EVT devices tailored to thrombus composition.
Background The treatment effect of acromioplasty for chronic subacromial pain syndrome (SAPS) on long-term shoulder function and rotator cuff deterioration has still to be determined. This study ...aimed to determine the long-term clinical and radiologic treatment effect of arthroscopic acromioplasty in patients with chronic SAPS. Methods In this double-blind, randomized clinical trial, 56 patients with chronic SAPS (median age, 47 years; age range, 31-60 years) were randomly allocated to arthroscopic bursectomy alone or to bursectomy combined with acromioplasty and were followed up for a median of 12 years. The primary outcome was the Constant score. Secondary outcomes included the Simple Shoulder Test, visual analog scale (VAS) for pain, VAS for shoulder functionality, and rotator cuff integrity assessed with magnetic resonance imaging or ultrasound. Results A total of 43 patients (77%) were examined at a median of 12 years' follow-up. Intention-to-treat analysis at 12 years' follow-up did not show a significant additional treatment effect of acromioplasty on bursectomy alone in improvement in Constant score (5 points; 95% confidence interval, −5.1 to 15.6), Simple Shoulder Test score, VAS score for pain, or VAS score for shoulder function. The prevalence of rotator cuff tears was not significantly different between the bursectomy group (17%) and acromioplasty group (10%). Conclusions There were no relevant additional effects of arthroscopic acromioplasty on bursectomy alone with respect to clinical outcomes and rotator cuff integrity at 12 years' follow-up. These findings bringthe effectiveness of acromioplasty into question and may support the idea of a more conservative approach in the initial treatment of SAPS.
Currently, acute ischemic stroke is still a leading cause of mortality and morbidity. Approximately 2 years ago, mechanical thrombectomy was proven beneficial as a revolutionary new therapy for ...stroke in the MR-CLEAN trial (A Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands). However, the mechanisms by which the thrombectomy device, or stent-retriever, interacts with the thrombus are largely unknown. A better understanding could lead to improved efficacy of mechanical thrombectomy devices.
Seven stent-retrievers with thrombi still entrapped were collected directly after thrombectomy. The stent-retrievers were studied using micro computed tomography, followed by scanning electron microscopy and light microscopy. Two independent observers rated interaction type and thrombus surface structure (porous filamentous or dense) at the interaction sites.A total of 79 interaction sites between thrombus and stent-retriever were categorized. Thrombus-stent-retriever interaction was found to be adhesive (n=44; 56%) or mechanical (n=35; 44%). Adhesive interaction was most frequently observed at interaction sites with a dense surface, compared with interaction sites with a porous filamentous fibrin surface (38/58; 66% versus 6/21; 29%,
=0.011).
The interaction between thrombus and stent-retriever was predominantly adhesive, not mechanical. Adhesive interaction was strongly associated with the presence of a dense thrombus surface without a porous filamentous fibrin network.
BackgroundIntra-arterial treatment (IAT) improves outcomes in acute ischaemic stroke. Presence of collaterals increases likelihood of good outcome. We investigated whether variations in the circle of ...Willis (CoW) and contributing carotid arteries influence outcome in patients who had a stroke treated with IAT.MethodsCT angiography data on patients who had an acute stroke treated with IAT were retrospectively collected. CoW was regarded complete if the contralateral A1 segment, anterior communicating artery and ipsilateral posterior communicating artery were fully developed, and the P1 segment was visible. Carotid artery contribution was studied with a self-developed carotid artery score ranging from 0 to 2 depending on the number of arteries supplying the occluded side of the CoW. Good clinical outcome was defined as modified Rankin Score ≤2 and measured at discharge and 3 months. We calculated risk ratios for the relation between completeness of the CoW, carotid score and good outcome, and performed a trend analysis for good outcome according to the carotid score.Results126 patients were included for analysis. Patients with a complete and incomplete CoW had a comparable risk for good outcome at discharge and 3 months. A higher carotid score was associated with a higher likelihood of good clinical outcome (p for trend 0.24 at discharge and 0.05 at 3 months).ConclusionIn patients with acute ischaemic stroke treated with IAT, chances of good clinical outcome tended to improve with number of carotid arteries supplying the cerebral circulation. Completeness of the CoW was not related to clinical outcome.
Objectives
Vertebrobasilar stenosis is frequent in patients with posterior circulation stroke and it increases risk of recurrence. We investigated feasibility of duplex ultrasonography (DUS) for ...screening for extracranial vertebral artery stenosis and compared it with CT angiography (CTA).
Materials and Methods
We gathered data on 337 consecutive patients who had DUS because of posterior circulation stroke or TIA. Matching CTA studies were retrieved and used as reference. Stenosis on CTA was considered “significant” if >50%, at DUS if Peak Systolic Velocity (PSV) > 140 cm/s for the V1 segment and PSV > 125 cm/s for the V2 segment. We determined the area under the ROC curve (AUROC). In addition, we calculated which PSV cut‐off value resulted in highest sensitivity with acceptable specificity.
Results
DUS was able to make an adequate measurement in 378 of 674 V1 segments and 673 of 674 V2 segments. DUS detected a significant stenosis in 52 of 378 V1 segments; 12 were confirmed by CTA (AUROC 0.73, 95% Confidence Interval 0.63–0.83). The optimal DUS PSV cut‐off value for this segment was 90 cm/s. For the V2 segment there were too few stenoses to allow reliable assessment of diagnostic characteristics of DUS.
Conclusions
Although DUS has a fair AUROC for detecting significant stenosis, adequate assessment of the V1 segment is often not possible due to anatomic difficulties. Assessment of the V2 segment is feasible but yielded few stenoses. Hence, we consider usefulness of DUS for screening of extracranial vertebral artery stenosis limited.
Although duplex ultrasonography is fairly capable of detecting significant extracranial vertebral artery stenosis, adequate assessment of the V1 segment is often not possible due to anatomic difficulties. Assessment of the V2 segment is feasible but yielded few stenoses. Hence, we consider usefulness of DUS for screening of extracranial vertebral artery stenosis limited.
Patients with unknown time of stroke onset (UOS) represent around one-third of ischemic stroke patients. These are patients with wake-up stroke (WUS) or daytime-unwitnessed stroke (DUS), often ...presenting outside the time-window for reperfusion therapy. UOS patients presenting between 4.5 and 12 h after time of last-seen-well were included. Clinical and imaging characteristics were compared between WUS and DUS patients. Good functional outcome was defined as a modified Rankin scale of ≤2 at follow-up. Sixty-one UOS patients were included: 42 WUS and 19 DUS patients. Stroke severity at presentation was mild to moderate with a median National Institutes of Health Stroke Scale of 5 in WUS and 6 in DUS patients. Time between last-seen-well and presentation at the hospital was shorter in patients with DUS compared to WUS (506 vs 362 min,
p
< 0.01). CT imaging results were similar, with a median Alberta Stroke Program Early CT Score of 10 for both WUS and DUS patients. After correction for age and NIHSS at presentation, no difference in good functional outcome was found between WUS (52%) and DUS (22%). In patients with unknown onset ischemic strokes presenting between 4.5 and 12 h after time of last-seen-well, clinical and radiological features were in large part similar between WUS and DUS. The outcome in the overall cohort was rather poor despite a favorable neuroimaging profile at presentation. These findings underscore the need for clinical trials in patients in whom stroke onset time is unknown.
Objectives
Thrombus computed tomography (CT) characteristics might be used to assess histopathologic thrombus composition in patients treated with endovascular thrombectomy (EVT) for acute ischemic ...stroke (AIS). We aimed to assess the variability in thrombus composition that could be predicted with combined thrombus CT characteristics.
Methods
Thrombi of patients enrolled in the MR CLEAN Registry between March 2014 and June 2016 were histologically analyzed with hematoxylin-eosin staining and quantified for percentages of red blood cells (RBCs) and fibrin/platelets. We estimated the association between general qualitative characteristics (hyperdense artery sign HAS, occlusion location, clot burden score CBS) and thrombus composition with linear regression, and quantified RBC variability that could be explained with individual and combined characteristics with
R
2
. For patients with available thin-slice (≤ 2.5 mm) imaging, we performed similar analyses for general and quantitative characteristics (HAS, occlusion location, CBS, relative thrombus density, thrombus length, perviousness, distance from ICA-terminus).
Results
In 332 included patients, the presence of HAS (
aβ
7.8 95% CI 3.9–11.7) and shift towards a more proximal occlusion location (
aβ
3.9 95% CI 0.6–7.1) were independently associated with increased RBC and decreased fibrin/platelet content. With general characteristics, 12% of RBC variability could be explained; HAS was the strongest predictor. In 94 patients with available thin-slice imaging, 30% of RBC variability could be explained; thrombus density and thrombus length were the strongest predictors.
Conclusions
Quantitative thrombus CT characteristics on thin-slice admission CT improve prediction of thrombus composition and might be used to further guide clinical decision-making in patients treated with EVT for AIS in the future.
Key Points
• With hyperdense artery sign and occlusion location, 12% of variability in thrombus RBC content can be explained.
• With hyperdense artery sign, occlusion location, and quantitative thrombus characteristics on thin-slice (≤ 2.5 mm) non-contrast CT and CTA, 30% of variability in thrombus RBC content can be explained.
• Absolute thrombus density and thrombus length were the strongest predictors for thrombus composition.
Background Multiple randomized controlled trials have demonstrated that mechanical thrombectomy with stent-retrievers (SR) is beneficial for patients with acute ischemic stroke (AIS) caused by ...thrombotic intracranial large vessel occlusion. SR, with thrombi entrapped (Fig. 1), were prepared for scanning electron microscopy (SEM) to analyze SR-thrombus interactions and associated thrombus surfaces at all interaction sites1. 94 interaction sites were analyzed by SEM by two independent raters.
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